The subject of the present invention is a scroll compressor equipped with deflector plate opposite the gas inlet orifice of its shell.
A scroll compressor comprises a hermetically sealed shell inside which are formed a suction chamber with an inlet for the gas and a discharge chamber or pressure chamber. The suction chamber and the discharge chamber are separated by a separating wall. A pump is intended to raise the pressure of the suction gas consists of two scrolls: a stationary scroll secured to the separating wall and a moving scroll driven by a shaft of an electric motor mounted inside the suction chamber. The moving scroll is off-centred with respect to this shaft so as to describe an orbital movement and delimit, with the stationary scroll, as the shaft rotates, pockets of varying and increasingly small volume in which the gas is compressed before escaping through an orifice towards the discharge chamber.
Because there are functional clearances between the stationary scroll and the moving scroll which together delimit the pockets in which the gas is compressed, it is necessary for the gas let into the pockets to be slightly laden with oil so that this oil can seal between the pockets to achieve reasonable compression during operation of the compressor.
It would therefore be desirable for the gas let into the suction chamber to be able to become uniformly laden with oil to a sufficient degree so as to optimize this sealing.
It is known practice, particularly from document U.S. Pat. No. 5,055,010, for a scroll compressor to be fitted with a deflector arranged inside the suction chamber opposite the gas inlet thereinto. Such a deflector is intended to distribute the stream of gas towards the two inlets of the compression stage, increasing the performance of the compressor in terms of energy consumption by allowing some of the gas to pass directly into the compression stage.
However, an arrangement of this type is not able to solve the problem which consists in allowing the gas to become uniformly laden with oil particles at the two inlets to the compression stage. This is because although the proportion of the stream of gas which is deflected towards the bottom of the compressor by the deflector follows a lengthy path inside the compressor within the suction chamber, allowing it to become laden with oil, the proportion of the gas which is deflected directly towards the compression stage does not become laden with oil, or becomes laden with very little oil, when there is a suction effect between the deflector and the inlet to the compression stage located above the deflector.
The object of the invention is to provide a scroll compressor equipped with a deflector opposite the gas inlet orifice to the suction chamber, the gas conveyed to the compression stage becoming more or less uniformly laden with oil particles.
This object is solved by providing a scroll compressor having a cylindric hermetically closed shell, a suction chamber within the shell, a scroll mechanism in the shell, lubrication mist generating elements, a suction gas inlet opening radially into the suction chamber and a deflector plate in overlying relationship with the suction gas inlet and cooperating with the shell to delimit a duct having at least an upper opening feeding suction gas to the scroll mechanism characterized in that the upper opening is shaped to deflect suction gas into a region within the suction chamber where an oil mist is generated by said mist generating elements during operation.
Preferably, the means generating an oil mist are constituted by a counterweight secured to the shaft of the motor and located in the suction chamber.
The proportion of the stream of gas directed by the deflector towards the compression stage does not flow directly towards this compression stage but is returned towards the inside of the suction chamber where the gas becomes laden with oil particles.
According to one embodiment of this device, the compression-stage end of the deflector has a L-shaped return which deflects the stream of gas through 180xc2x0.
Advantageously, the end of the L-shaped return is located approximately in the same plane as the upper edge of the duct formed by the deflector.
This arrangement thus creates a baffle effect.
According to one feature of the device according to the invention, the deflector consists of a part of overall xcexa9-shaped cross section, the flanges of which are used for securing it to the internal face of the shell approximately parallel to the axis of the compressor, and the body of which delimits the duct conveying the gas towards the inside of the suction chamber.
According to one embodiment of the invention, the duct delimited by the deflector is also delimited by a recess made in the inner face of the shell of the compressor.
Preferably, the duct has an upper opening and a lower opening and comprises two parts, of which the one facing towards the compression stage has a smaller cross section than the one facing towards the motor.
To achieve good distribution of the flows, the gas inlet orifice opens into the part of the duct of larger cross section facing towards the motor, the section-reducing zone providing the transition between the two parts of the duct being offset towards the compression stage with respect to the inlet orifice.
According to one embodiment of this device in its small cross section zone facing towards the compression stage, the deflector has a flat central surface whereas, in its large cross section zone facing towards the motor, the deflector has a central surface in the shape of a portion of a cylindrical surface.
According to another feature of the invention, the length of the deflector is such that this deflector extends on each side of the inlet orifice over a distance at least equal to the diameter of the inlet orifice.